CR should only be around 10.5:1, running 93 octane pump gas. Oil pressure is 80psi cold, about 50psi once its warmed up.
I put a differential pressure gauge on the dipstick, and its reading 1.5 to 2 inches negative pressure until I whack the throttle to 5500-6000, then it slams to positive 2"! I do have a breather on one valve cover, and a PCV on the other into the carb base/manifold vac.

I wouldn't think 2" would blow a dipstick out. Was this test just a quick rev or under load? Which breather do you specifically have? Some of them leave a lot to be desired as far as flow but look pretty. You can look at PCV flow too. At w.o.t it won't really be sucking but it does provide a path for pressure to escape. Sounds like a leak down test is in order too. The only engines I've had the dipstick blown out of were either shot or detonating itself to death. Clay_________________I have done so much with so little for so long, I can now do anything with nothing.

I mostly see it happen under no load. The pressure may be more than 2", that's the max reading on the gauge. The point is, it spikes for some reason at the higher rpms. I just have a Mr Gasket chrome breather, on alum. valve cover with no baffles. Theres evidence of oil out the breather cap too. I guess the primary cause for pressure in the bottom end is blowby, I will have to try a leakdown test.

Do I need to bother with the PCV, or maybe take it out and replace with additional breathers in the valve covers? Theres only about 9 inches vacuum at idle.

Even if you don't have the best PCV valve that isn't your problem. If I were in your shoes a leak down test would absolutely be the next step. If you're giving the pressure readings as inches of water pressure it really should pull more than that at idle. I've never actually measured it but just plugging the breather hole by hand on running engines I've felt some pretty good suction build up. Clay_________________I have done so much with so little for so long, I can now do anything with nothing.

Even if you don't have the best PCV valve that isn't your problem. If I were in your shoes a leak down test would absolutely be the next step. If you're giving the pressure readings as inches of water pressure it really should pull more than that at idle. I've never actually measured it but just plugging the breather hole by hand on running engines I've felt some pretty good suction build up. Clay

As Clay said, I would hope you have more inches of vacuum at idle. The power valve will be open otherwise.
At 2" positive will never blow the dip stick. You might be more like 2 ' lbs which is wrong. Do a leak down....

It could be that the at high RPM, the WOT lets the PCV close (no vacuum, so the spring closes it). That could be the cause of the spike in pressure I saw on the gauge. Especially if the breather cap is restricted, or too small to allow the volume of pressure out. Can you recommend a good push-in breather?

what oil are you running? sounds silly but sometimes the oil can screw with ring seal. ive encountered this phenomenon two times in 20 years. unlikely but it does happen. other than that.... what they said. leak down test!_________________

Without baffles in a valve cover you are probably going to have oil coming out of about any breather you run. You might as well make some baffles to go inside your valve covers. I run a K & N style clamp on breather from our local speed shop. I had to take the baffles out of these valve covers but the stud girdles are pretty close to the valve covers and shield the breather outlet pretty good. I originally made this offset breather pipe to clear supercharger plumbing but it helps with oil control also.
Mostly keep in mind you need to give oil droplets something to run into and not have a line of sight to the breather. Clay_________________I have done so much with so little for so long, I can now do anything with nothing.

doesnt sound like anything weird with the oil. might need to ditch the pcv and run some good valve cover breathers. like Clay said... you need baffles if youre going to use them. i would still do a leakdown._________________

The cam is pretty big ( duration) so the 9" at idle is probably about the best you are going to get. You just have to make sure the power valve is closing at idle probably a 7.5 or less. I have had engines do this before when they were new, and they got better after they had a few miles on them, like 500-2000 miles of break in. If you can I would run a 5/8" or bigger diameter hose from the breather into the base of the air cleaner. Basically a stock set up which should flow enough air to keep the dip stick in. The other thing is check to make sure the dip stick is not hitting the crank, and being knocked out because of the mechanical contact. How many miles are on this engine?

If you can I would run a 5/8" or bigger diameter hose from the breather into the base of the air cleaner. Basically a stock set up which should flow enough air to keep the dip stick in. The other thing is check to make sure the dip stick is not hitting the crank, and being knocked out because of the mechanical contact. How many miles are on this engine?

This motor is basically brand new. less than 50 miles on it, but the car isn't street legal, so I can only run it at the track. It was spraying oil under the hood during burnout, when I found the dipstick pushed up about 4 inches, that's why I suspect crankcase pressure. I wasn't running an air cleaner, I can add one and try plumbing the breather to it like you suggested.

Please get an air cleaner on it. It'll save you money in the long run. How long is the dipstick tube? If it's what I call the "normal" style that is about 8" long vibration probably isn't a problem but if it's some different long style that isn't supported at the top vibration is another possibility. I'm leaning toward ring seal because of the lack of more crankcase vacuum at idle. Clay_________________I have done so much with so little for so long, I can now do anything with nothing.

I did not realize it was a track car. In that case a cheap fix would be to weld a couple pieces of pipe into the header collectors at a 45degree angle, threaded for a couple of smog tube check valves, and run a hose from each valve cover to the check valves.

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